Ex-Arsenal trainee Blackman joins Celtic
The 21-year old has been training with the Hoops in recent weeks and has impressed enough to win an undisclosed deal to make Parkhead his temporary home.
Blackman, who was with the Gunners between 2001 and 2006 as a junior, has been out of contract since departing AFC Wimbledon last year but will now get the opportunity to experience the Scottish Premier League.
"He's a kid who was out of contract and he was recommended by an agent friend of mine," said Celtic boss Neil Lennon regarding Blackman who can be deployed as a full-back or in midfield.
"We had a good look at him for two or three weeks and he's a hungry boy who wants to make a name for himself."